Filter cartridge



April 17, 1956 J. w. F'GWELL 2,742,160

FILTER CARTRIDGE Filed June 14, 1951 INVEN TOR.

JOSEPH W. FUGWELL 2,742,160 FILTERCARTRIDGE JoseplrW. Eogwell, Lakewood,vliio y, Applicafionaunelia; i951, serialiNo. :31,5051 6 claims. (Cl. 21o-169) l `'Iliis inventionI relates ingeneral` to filters and more particularly to thick-walledcylind'rical filter cartridges for j An-'object'lof the invention is= the provision otw a-.ilter cartridge wlii'cl'i will permit thev liquid, which 1s:` to4 be -ltered; 'to-pass Afrom the outer'cylindrical'reglont'tolv the inner cylindrical region; such that the larger: particles are n l'tered out'or` collected inlthe outer cylindricalregionof tli'ecartridge; and such' that the` smaller particles may pas'slradially through the Wall of? thecartridge` towards theV innerv cylindrical! region where they' are; filtered. out orf collected; the smallest of the particlesV beingsubstantially allcollectedor filtered out atthe very inner cylmf dificalf region: of` the cartridge.

An'otlien object' of the inventionissthe provision; of and the-`prooess1lfori making. a1 thick-walled. cylindricall filterl cartridgezhavin'g alltermediumV assemblediwithvarying compactness; `bothin a spiral` direction and in@ a. radial directiom Another, objectzof the invention is' the provision: of and' the' process for: makingl al thick-walled cylindricali filtert cartridge I having` a1 filter,` medium assembled with r varying oorilp'actness',` both" in"v a'spiral direction and in. a-k radiali direction;A the: compactness kdecreasing uniformlyf inA an outward spiral direction from one point on-,theaspiralto a-.isecondpointonz thespiral and decreasing abruptly. 1n an outwardfradial. direction from( one-convolution tot-the Another: object: of the `invention is `theprovislony of." and Y the: processr for; making a` thickawalledl .cylindrical' Iilter cartridge havin'gf a t filtering medium assembled .tol producebruptlchangeslint compactness in arradial direction and to produce gradual changes inicomp'actnessin' a spn'al' direction. y

@ther objects; and afuller understanding-of` themven-` Figureidisa pl'ansviewoffamodiedfformoffthe.car= Y tridge" shown'iir Figure'l. p Y

Withreference tol Figurev lA ofi' tlicdawing; g the thick# @rencel character 1f0-andi comprises generally* a= tubular coro 1I; abackingstrip anda filtering-'medium lvtv Asfillust'rated,y tl'ie: backing` strip*- 1-2`i and the filtering' medium 1.",` are SpirallytvvrappedlY around thetubular core 11 ln the: drawing; Lfurspirali convolutions' are illus-- tratedby the reference characters 121i 15;' 16 and'f1-' 7but Y it is@ to bej understood tirata-nyv numbero spiral convoluflow radially therethrough. In-Figure-2 av modiiiedfrm p off thertubular core 'is-' shown and is' illustrated byv the reference character; 2'2' Wlicl has a plurality of radial' openings zttherein, producing a-perforatedcore through whichthe--filteredliquid may radill'y'bw. In Figure l, the wall` off the screeny is-illustrated= by the; reference characterl 19'; The filtering material 13l is` assembled` with Varying compactness; Botiiin a spiraldirectiorrand'ina radiali direction',l the compactness` decreasing' uniformly ini an' out-ward; spiral direction fromV one point` on the spiral to'` a; second point' on' the spiral and decreasing abruptly-in an'- outward radiali direction from one iconvolutionto the next.V Theeoutsideendfztlof the backingv strip'A -1'2t isprovidedwith an' adhesivefor bonding material 24, see Figure 7, `so that the convolutions are secured1 against? unwinding'. r The bonding; materialv 24 tionmay-'be had'by referringzto the'follo'wing description` 50 and"v claims taken ihr conjunction withihe accompanying drawing; ,imwliicht Figure: 1" isaperspectiveview 'of` a thickawalled cylin-l drical'lte'r; cartridge. embodying the features'- of the invention; parts being broken away: to illustrate thel internal construction-thereof; l

Figure 2 is a perspective view of a modied tubularv eoreithaving'l perforations `therein which may be :employed insteadlof thescreen tubular coreshown in l-igurel;V

Figure 3 is atview `similar to Figure l and. shows; the assembly without any reinforced tubular core;

Figure 4 is a side view of an apparatus for carrying out t,he processtV for making athickfwalled cylindrical filter bondsitliet outside i end 2`0`v of the -latst' convolution' toV the tnlitside of: the next adjacent convolution. t While aV bond:- ingj material has* been; employed to secure the convoluL tions against unwinding, itfis'to lie/understood thattotlier,

means may- `be employed suchJ as 1 sewing; Y

In Figures 4 and 5, an apparatus is illustrated forear-- ryingout the process off constructing' the thick-walled cylindrical filter-cartridge. As illustrated; ,they apparatusA comprisesi principally a? hatA table 27 f' `having upwardly the longitudinall marginalv edges 4S" of' the backing strip Y are folded-` overA the edgesA off theV filtering mediumI pand' advanced lend ofJ the ybacking strip is adapted to Vbe wound aroundamandrel 30 whichis driven by a motor 3'4.

Themandrel'y Sthas a fixed-side `flange 3:1 andaI removable; sidellangeV V32 which' ismounted upon the @mam drel by means `offa set' screw 33. ,The object of thev re-k movable side ilange Zizis to enabley the lter cartridge to) be removedafter it isoncey formed. 4As the backing stripv V12 andi thelterj mediumy 134 are' spirally'wrapped t around the mandrel; `they are pressed by means of a press` roll' 35= which is carried 'byftwo' side leveraarmsl 36 pivotally mountedlupon a pivot-37. AVsshowninfFigure` 4,

, thefright-handend ofi-the lever arms-36' aregprovided :with

i a weight :'18 so th'atthe-press roll 3S is urged againsttheV mand'rel'.V ,During'thelprocess offspirall'y Winding. the backingstrip 1'2 Vand tlie filteringmedium 13 around' the mandrel 30, the press roll 35' is urged toward the inan-l a hydraulicA cylindcr 39l- The, pressure of-"the hydraulic uidtisfgovernedl by, means of a regulator pressure valve.

l indicated generally by.therreference characterstlzA The y 2,742,160v ytented l Apr." 17, 1956 3 function of the regulated pressure valve'41 isto control the pressure within the cylinder 39 in accordance with the rotation of the press roll 35. As illustrated, the

l regulated pressure valve 41mayjbeumechanically connected by any suitable means A to the mandrel 30, the

mechanical means being illustrated diagrammatically by the dash-dot line 42. During the first convolution which is indicated by the reference character 17, the hydraulic pressure ofY theiiuid within the cylinder 39 is of a high vValue thereby compactingV the filtering medium with high pressure. As the regulating pressure valve 41 is turned by the mechanical means illustrated by the dot-dash line, the pressure within the cylinder gradually decreases V uniformly as the filtering medium is spirally wound around the mandrel. The resultant effect of the varying pressure is such that the radial depth of the inner convlution 17 is less than the convolution 16, and the convolution 16 is less than the convolution 15, and the convolution 15 is less than the outer convolution 14. Accordingly the compactness of the filtering medium decreases uniformly in an` outward spiral directionfrom one convolution to the next or from one point on a convolution to a second point on a convolution.

In Figure 3, the tubular core is constructed of theback-v ing strip 12 andthis construction is effected by making at least one complete convolution of the backing strip 12 before the filter medium rreaches the mandrel. The wall of the tubular core inFigure 3 is indicated by the reference character 25. In Figure 7, the advanced end of the backing strip 12 is indicated by the reference character 25 and this constitutes the beginning of the wrapping of the backing strip into the first convolution to 'make the wall 25 of the coreof the same material as the backing strip.

In constructing the filter cartridge shown in Figure l, the sc reen tubular core 11 is first mounted around the mandrel 30 before the spiral wrapping process is initiated. Similarly, in producingalter cartridge with a perforated core as shown in Figure 2., the perforated core is first inserted over the mandrel 30 before starting the Wrapping process. Y

In Figure 6, there is shown Ya modified arrangement of the Wrapping apparatus in that an additional mandrel 50 is employed which becomes thefinal wrapping mandrel withY the result that themandrel 30 and the press roll 35 become merely pressing rolls to control the Vthickness of the filtering medium 13. The mandrel 50 is motor driven and has Va side flange which-may be removed by means of a set screw 51. InFigure 6, the filtering. mediurn isk disposed upon 'the backing Vstrip such that the filtering medium at the advanced end 43 of the backing strip is deeper or thicker than the filtering medium at the rearward end of the backing strip. In Figure 4, the depth vof the filtering medium is distributed at substantially a uniform depth and the pressure of the press roll 35 is varied to control the degree of compactness. In Figure 6, the press roll 35 is hydraulically positioned at a fixed point by the piston 40 being hydraulically locked in place within the cylinder 39 by entrapping fluid therein by the pressure valve 41V, with the result that the rolled thickness of the lteringjmedium 13 is substantially uniform, as shown by the convolutions 44 in Figure 8 which represents the top view of a filter cartridge made by this method. In other words, the spacing between the press roll 35v and the mandrel 30is maintained substantially constant `during the spiralingfoperation, inasmuch as the filteringfmateriallli at 'the advance end of the backing strip 12 is piled' deeper than at' the rearward end, the compactness of the filtering medium for the inner convolutions is greater Vthan thatfor the outer convolutions. The Figure 6 thusrepresentsa modified process for obtaining a varying compactness.

In the operation of the apparatus in Figure 6, the regulatedpressure valve 41 is de-clutched from the mandrel 3D by pulling out on a knob 52 which knob Sets the pressure ofthe fluid within the hydraulic cylinder 39V; Other elements may be employed to vary the degree of compactness but the arrangements shown in Figures 4 and 6 are particularly adaptable for carrying out the process in making the filter cartridge.

The backing strip 12 may be constructed of cloth, wire screen, filter paper or any other porous strip. The filtering medium 13 may be selected from a filter class consisting of diatomaceous earth, vermiculite, kieselguhr and fullers earth, cotton waste, Woolen waste, synthetic ber waste, wood pulp, straw bers, foam rubber, foam plastic, and foam material, or a combination of one or more of the above listed filter mediums. The filtering medium 13 may be bulk or loose material, or may be pre-formed by suitable felting means or by pre-molding.

A cylindrical cartridge constructed in accordance with the present invention provides a medium through which the liquid to be filtered may iiow from the outside thereof towards the inner core thereof. As the filtered liquid flows from the outside to the inside thereof, the large particles are lirstlter'ed out by the outer convolutions. As the liquid passes radially inwardly towards the central core, it encounters abrupt changes in compactness as it passes from each convolution to the next. These abrupt changes provide an opportunity for the filtered liquid to then spread spirally which operates to distribute the particles that are to be filtered out. The action ofthe filter is such that substantially all the finest particles are filtered out by the inner convolution. Accordingly, the lter cartridge may become highly saturated or ,loaded with well distributed filtered particles in a radial direction, thus rendering the filtered cartridge highly eiiicient. If the small particles were permitted to be filtered out near the outer convolution, then these small particles would clog'up the filter cartridgeand would prevent the inner convolutions of having'the opportunity to become useful. Therefore, in the'present invention, the fact that 'the compactness decreases uniformly in an outward spiral direction from one point on the spiral to a-second point on the spiral while decreasing abruptly in an outward radial direction from one convolution to the other, is an important feature of the invention.

Although this invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred forrn has been made only by way of example and that numerous changes in the details of construction and the combination and karrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed. y

' What is claimed is:

1. A filter cartridge comprising a previous central core,

"i a layer of filtering material spirally Vwound about said coreand formed throughout its length in increments of progressively and gradually decreasing thickness from the core outwardly, each successive convolution having a body compactness and density differing substantially from that of the adjacent convolution, a backing strip .forsaid layer, and means for securing saidconvolutions in Vtheir'spiral form. Y

the next, and increases abruptly in a radial direction from l one convolution to the next.

4. A filter cartridge according to claim l, in which the layer of filter material has gradual changes in compactness, thickness and density in a spiraldirection, said changes being abrupt in a radial direction, in each layer.

`5. A lter cartridge according to claim 1, in which the backing strip also constitutes the core. 6. A filter cartridge-according to claim l, in which the backing strip has marginal edges folded over the side edges of the lter layer. 5

References Cited inthe le of this patent UNITED STATES PATENTS Warner Dec. 20, 1938 Brundage Dec. 27, 1938 Y Baldwin Jan. 5, 1954 

